Revitalization is the period in a neighborhood's life cycle when it is "rediscovered" because of modest prices and convenience to employment, shopping, etc. The neighborhood is revitalized as people move in and modernize the houses. Many old neighborhoods near downtown areas are entering the revitalization cycle all over the country because of close-in convenience and high prices of suburban houses.
When older houses are purchased for rehabilitation and renovation, the area is undergoing "gentrification". Gentrification is not considered a neighborhood life cycle but it is certainly important to the revitalization stage.